powerpc: Always use SPRN_SPRG_HSCRATCH0 when running in HV mode

This uses feature sections to arrange that we always use HSPRG1
as the scratch register in the interrupt entry code rather than
SPRG2 when we're running in hypervisor mode on POWER7.  This will
ensure that we don't trash the guest's SPRG2 when we are running
KVM guests.  To simplify the code, we define GET_SCRATCH0() and
SET_SCRATCH0() macros like the GET_PACA/SET_PACA macros.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 13 insertions, 13 deletions

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 805e20657868..e513c1d35b2a 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -43,7 +43,7 @@ __start_interrupts:
 _machine_check_pSeries:
         HMT_MEDIUM
         DO_KVM  0x200
-        mtspr   SPRN_SPRG_SCRATCH0,r13          /* save r13 */
+        SET_SCRATCH0(r13)
         EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common, EXC_STD)
 
         . = 0x300
@@ -51,7 +51,7 @@ _machine_check_pSeries:
 data_access_pSeries:
         HMT_MEDIUM
         DO_KVM  0x300
-        mtspr   SPRN_SPRG_SCRATCH0,r13
+        SET_SCRATCH0(r13)
 BEGIN_FTR_SECTION
         GET_PACA(r13)
         std     r9,PACA_EXSLB+EX_R9(r13)
@@ -67,7 +67,7 @@ BEGIN_FTR_SECTION
         std     r11,PACA_EXGEN+EX_R11(r13)
         ld      r11,PACA_EXSLB+EX_R9(r13)
         std     r12,PACA_EXGEN+EX_R12(r13)
-        mfspr   r12,SPRN_SPRG_SCRATCH0
+        GET_SCRATCH0(r12)
         std     r10,PACA_EXGEN+EX_R10(r13)
         std     r11,PACA_EXGEN+EX_R9(r13)
         std     r12,PACA_EXGEN+EX_R13(r13)
@@ -81,7 +81,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_SLB)
 data_access_slb_pSeries:
         HMT_MEDIUM
         DO_KVM  0x380
-        mtspr   SPRN_SPRG_SCRATCH0,r13
+        SET_SCRATCH0(r13)
         GET_PACA(r13)
         std     r3,PACA_EXSLB+EX_R3(r13)
         mfspr   r3,SPRN_DAR
@@ -95,7 +95,7 @@ data_access_slb_pSeries:
         std     r10,PACA_EXSLB+EX_R10(r13)
         std     r11,PACA_EXSLB+EX_R11(r13)
         std     r12,PACA_EXSLB+EX_R12(r13)
-        mfspr   r10,SPRN_SPRG_SCRATCH0
+        GET_SCRATCH0(r10)
         std     r10,PACA_EXSLB+EX_R13(r13)
         mfspr   r12,SPRN_SRR1           /* and SRR1 */
 #ifndef CONFIG_RELOCATABLE
@@ -120,7 +120,7 @@ data_access_slb_pSeries:
 instruction_access_slb_pSeries:
         HMT_MEDIUM
         DO_KVM  0x480
-        mtspr   SPRN_SPRG_SCRATCH0,r13
+        SET_SCRATCH0(r13)
         GET_PACA(r13)
         std     r3,PACA_EXSLB+EX_R3(r13)
         mfspr   r3,SPRN_SRR0            /* SRR0 is faulting address */
@@ -134,7 +134,7 @@ instruction_access_slb_pSeries:
         std     r10,PACA_EXSLB+EX_R10(r13)
         std     r11,PACA_EXSLB+EX_R11(r13)
         std     r12,PACA_EXSLB+EX_R12(r13)
-        mfspr   r10,SPRN_SPRG_SCRATCH0
+        GET_SCRATCH0(r10)
         std     r10,PACA_EXSLB+EX_R13(r13)
         mfspr   r12,SPRN_SRR1           /* and SRR1 */
 #ifndef CONFIG_RELOCATABLE
@@ -272,7 +272,7 @@ masked_interrupt:
         rotldi  r10,r10,16
         mtspr   SPRN_SRR1,r10
         ld      r10,PACA_EXGEN+EX_R10(r13)
-        mfspr   r13,SPRN_SPRG_SCRATCH0
+        GET_SCRATCH0(r13)
         rfid
         b       .
 
@@ -285,7 +285,7 @@ masked_Hinterrupt:
         rotldi  r10,r10,16
         mtspr   SPRN_HSRR1,r10
         ld      r10,PACA_EXGEN+EX_R10(r13)
-        mfspr   r13,SPRN_SPRG_HSCRATCH0
+        GET_SCRATCH0(r13)
         hrfid
         b       .
 
@@ -293,7 +293,7 @@ masked_Hinterrupt:
 do_stab_bolted_pSeries:
         std     r11,PACA_EXSLB+EX_R11(r13)
         std     r12,PACA_EXSLB+EX_R12(r13)
-        mfspr   r10,SPRN_SPRG_SCRATCH0
+        GET_SCRATCH0(r10)
         std     r10,PACA_EXSLB+EX_R13(r13)
         EXCEPTION_PROLOG_PSERIES_1(.do_stab_bolted, EXC_STD)
 
@@ -305,14 +305,14 @@ do_stab_bolted_pSeries:
       .align 7
 system_reset_fwnmi:
         HMT_MEDIUM
-        mtspr   SPRN_SPRG_SCRATCH0,r13          /* save r13 */
+        SET_SCRATCH0(r13)               /* save r13 */
         EXCEPTION_PROLOG_PSERIES(PACA_EXGEN, system_reset_common, EXC_STD)
 
         .globl machine_check_fwnmi
       .align 7
 machine_check_fwnmi:
         HMT_MEDIUM
-        mtspr   SPRN_SPRG_SCRATCH0,r13          /* save r13 */
+        SET_SCRATCH0(r13)               /* save r13 */
         EXCEPTION_PROLOG_PSERIES(PACA_EXMC, machine_check_common, EXC_STD)
 
 #endif /* CONFIG_PPC_PSERIES */
@@ -327,7 +327,7 @@ slb_miss_user_pseries:
         std     r10,PACA_EXGEN+EX_R10(r13)
         std     r11,PACA_EXGEN+EX_R11(r13)
         std     r12,PACA_EXGEN+EX_R12(r13)
-        mfspr   r10,SPRG_SCRATCH0
+        GET_SCRATCH0(r10)
         ld      r11,PACA_EXSLB+EX_R9(r13)
         ld      r12,PACA_EXSLB+EX_R3(r13)
         std     r10,PACA_EXGEN+EX_R13(r13)